It is known that absorption bodies intended to form part of absorbent articles should have a sufficient absorption capacity and a capability to take up rapidly escaping liquid when for example an incontinent adult wearer of the article empties their entire bladder in an uncontrolled manner.
Depending on what the absorbent article is intended for, the absorption capacity varies within wide boundaries, for example, a capacity of 4 grams is sufficient for the smallest size of a sanitary towel, while a capacity of over 1000 grams is required for the largest articles intended for incontinent adults.
To manufacture articles with sufficient absorption capacity is not a big problem today when there are gel-forming, highly absorbent particles, so-called superabsorbents, to mix in in the absorption bodies of the absorbent articles.
One type of problem with today's very thin and hard compressed articles is to ensure that the articles can take up liquid that is secreted and impacts on the article at a high flow rate. For example, absorbent articles for incontinent adult wearers should be able to take up several hundred ml of urine excreted in 10 seconds. If the absorbent article's absorption body is incapable of taking up and absorbing this large flow, there is a major risk that the urine runs on the surface of the article and out over the edge of this.
One solution to the problem of taking up rapidly secreted bodily fluid is to arrange special material layers between the absorption body and the user that are intended to take up and temporarily store fluid while waiting for the absorbent body to manage to absorb the fluid. Examples of such materials are resilient pads of polyester fibres, for example.
Another frequent solution is to create from today's thin, wide crotch structure a bowl-shaped structure between the wearer's thighs in which the fluid can temporarily be collected before it penetrates the absorption body. The articles' absorption bodies have been provided in this case with compressions, slits, contracting elastic elements or the like to control the shape of the articles when they are pressed together between the wearer's thighs in use.
In patent application GB 2,296,437 (Hansson et al Mölnlycke AB) it is described how the shaping of an absorbent article can be controlled when it is exposed to forces substantially perpendicular to the longitudinal direction of the article.
The article comprises an absorbent layer that has a through slit and a first material layer over one surface of the absorbent layer, and a second material layer over the opposing surface of the absorbent layer. One material layer is joined to the absorbent layer up to said slit, while the second material layer is not joined up to said slit. When the article is exposed to compressive forces directed perpendicularly to the slit, the article bends/is folded forcibly in the direction away from the unjoined side of the absorption layer.
In patent document WO 2011/105108 A1 (Mukai et al, Uni-Charm), a refined variant is described of an absorption body that is shaped between the user's thighs when the article is used.
The absorption body in WO 2011/105108 A1 consists of 2 layers, wherein the layer that is arranged away from the user has a longitudinal opening arranged centrally in the crotch part along the longitudinal centre line. The second absorption layer that is oriented nearest to the wearer of the article has side openings placed symmetrically between the longitudinal centre line of the layer and its respective longitudinal edge.
The document shows that the design of the absorption body with longitudinal openings in both absorption layers means that the absorbent article is shaped like a W in the crotch area when it is pressed together between a user's thighs.
It has proved to be the case, however, that, regardless of whether the article is designed to assume a simple bowl shape, a U- or V-shape, or a more sophisticated bowl shape, a W-shape, upon use, it is a problem that the article does not assume the intended shape when it is placed on a user.
It is not unusual, for example, for the article to assume an inverted shape when it is exposed to pressure forces from the user's thighs, meaning for example that the U-shape instead becomes an inverted U-shape ((∩-shape) and the W-shape becomes an inverted W-shape (M-shape).
It has also proved to be the case that articles intended to assume a U-shape, a V-shape or a W-shape when they are deformed in a transverse direction between the user's thighs have a rebound force against the user's thighs that is much too low, wherein the article is not able to effectively seal against the thighs when in use.
There is thus a need for improved absorbent articles that shape themselves in a desired manner with greater reliability when the article is placed and pressed together between a user's thighs. The requirement exists regardless of whether it is a question of absorbent articles intended for children or adults with urinary incontinence.
Furthermore, there is a need for an article which, in the deformed state according to the above, has an increased rebound force in a transverse direction against the user's thighs when in use.